WASHINGTON — The results of Tuesday’s elections could have a significant influence on how the United States deals with global warming in several ways.

In the Trump era, much of the action to fight climate change has been happening at the state level. On that front, the results were mixed: Several key climate policies on the ballot, including a carbon tax in Washington State and an aggressive renewable power target in Arizona, were defeated soundly. But Democrats who favor clean energy also took control of a number of key governorships and state legislatures, opening doors for expanded action.

On the national level, Democrats recaptured the House and are expected to put climate change back on the agenda, albeit cautiously. But the electoral churn also meant that one of the congressional Republicans who was, in theory, most open to engaging on the issue lost his seat.

Here are five key points from Tuesday:

Carbon taxes are a tough sell

Economists have long said that carbon taxes could be an important tool for fighting climate change. Make it more expensive to pollute, the theory goes, and companies will quickly find ways to reduce their emissions. The obstacle is that voters are rarely eager to embrace policies that increase the cost of energy.

Proponents of a carbon price in Washington State have now tried two different strategies to allay those concerns. In 2016, they proposed a carbon tax starting at $15 per ton that would have been offset with rebates, an approach favored by some conservatives. That ballot initiative failed.

Don’t look for big proposals at the national level

Democrats seized control of the House of Representatives, and that means climate change is back on the congressional agenda.

Eddie Bernice Johnson, the Texas Democrat who is expected to become chairwoman of the House Science Committee, has vowed to “address the challenge of climate change, starting with acknowledging it is real.” And Nancy Pelosi, widely expected to become speaker, said she would revive the select committee on global warming, a panel she initiated the last time Democrats controlled the chamber.

“We’re facing the challenge of climate change,” Gene Karpinski, president of the League of Conservation Voters, said Wednesday morning. “We know it’s more intense. We’ve seen the reports. We need action. And we have a chance to be on the offense in the House for the first time in a long time.”

But what form will that take and how far are Democrats willing to go on climate? Don’t look for sweeping policy like putting a price on carbon, analysts and activists say.

Even if a measure like a carbon tax did pass the House, it would sink in the Republican-held Senate and be denounced by President Trump. Aggressive oversight of the administration’s science and environment policies and its regulatory rollback efforts are more likely.

Expect action at the state level

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The governor-elect of Michigan, Gretchen Whitmer, has pledged to move the state to 100 percent carbon-free energy.CreditBrittany Greeson for The New York Times

After Mr. Trump’s disavowal of the Paris climate agreement, 16 states and Puerto Rico pledged to uphold the accord anyway and keep fighting climate change on their own. They may find new allies now.

Democrats won governorships in seven states that were not already part of this climate alliance: Illinois, Kansas, Maine, Michigan, Nevada, New Mexico and Wisconsin. All of the incoming governors in those states have called climate change a major problem. Two of them, Tony Evers of Wisconsin and Gretchen Whitmer of Michigan, have also pledged to move their states to 100 percent carbon-free electricity in the years ahead.

It remains to be seen what sorts of climate or clean-energy policies these new governors may try to enact, and some of them face divided legislatures. But there are already a few hints: In Maine, for instance, the governor-elect, Janet Mills, has vowed to overturn her predecessor’s moratorium on new wind turbines in the state.

Representing one of the most vulnerable parts of the country, where flooding caused in part by sea level rise has become a chronic problem, Mr. Curbelo broke with much of his party by acknowledging that human activity drives global warming and calling for a policy solution. This year he went a step further, becoming the first Republican in a decade to propose a tax on carbon emissions.

But neither that nor Mr. Curbelo’s moderate positions on issues like immigration were enough to save him from a shift of political winds that flipped his district blue and led his challenger, Debbie Mucarsel-Powell, to a narrow victory.

Some Democrats and environmental activists, describing Mr. Curbelo as a victim of voter antagonism toward Mr. Trump, made a case Tuesday that Mr. Curbelo’s loss would not deter other Republicans from engaging on climate change.

“It clearly didn’t hurt Carlos to display conviction and courage,” said Bob Inglis, a Republican former congressman from South Carolina who is working to get members of his party to accept climate change. “It only helped him. What hurt him was being tied to a party that’s tied to Trump.”

Mr. Inglis called the loss of Mr. Curbelo “a blow” to the bipartisan movement on climate change. But, he said, he believes the larger message of the congressman’s loss is that voters, particularly those experiencing the effects of global warming in their backyards, want to see action.

“What it should be is a call to Republicans to figure out a way to offer a solution consistent with Republican values,” Mr. Inglis said. “You want the majority back? Engage on climate.”

Other conservatives, like Grover Norquist, the president of Americans for Tax Reform, pinned Mr. Curbelo’s loss directly on his support for a carbon tax.

“Curbelo could and should have been re-elected but he was talked into pushing an energy tax on all Americans, the so-called carbon tax,” Mr. Norquist said. “As a result, voters kicked him out of office.”

Mixed results for renewable energy

Voters in Nevada approved a ballot measure that would require electric utilities to get 50 percent of their power from renewable sources by 2030, up from around 25 percent today. That measure will have to be approved again in 2020, but so far it has sailed through with surprisingly little resistance in a state that is already racing to lay more solar panels in the desert.

Yet in neighboring Arizona, a similar measure, which would have required utilities to get half their electricity from renewable sources by 2035, was overwhelmingly rejected after serious opposition from the state’s biggest power company.

A lesson: Wind and solar power may be popular, but they’re hardly above political wrangling, and supporters will have to overcome both well-funded opponents for renewable energy to continue its growth.

Brad Plumer is a reporter covering climate change, energy policy and other environmental issues for The Times's climate team. @bradplumer

Lisa Friedman reports on climate and environmental policy in Washington. A former editor at Climatewire, she has covered nine international climate talks. @LFFriedman

A version of this article appears in print on , Section F, Page 11 of the New York edition with the headline: Climate Change and the Midterm Elections: Five Takeaways. Order Reprints | Today’s Paper | Subscribe